An internal combustion engine-based system includes an internal combustion engine. The internal combustion engine-based system includes an engine interrupt connected to the engine. The engine interrupt is configured to selectively stop the operation of the engine. The internal combustion engine-based system includes a controller in communication with the engine interrupt. The internal combustion engine-based system includes a carbon monoxide detector in communication with the controller. The controller uses the engine interrupt to stop the operation of the engine when the carbon monoxide detector provides the controller with signals that are representative of a carbon monoxide level proximate the internal combustion engine that together form a trend of building carbon monoxide amounts over a set time interval.

A temperature sensor for a motor vehicle is disclosed. The temperature sensor includes a temperature-sensitive element, two electrical wires connecting the temperature-sensitive element to an electrical connector, an insulating sheath surrounding the two electrical wires, a protective endpiece including a closed end in which the temperature-sensitive element is housed, and a fixing means through which the insulating sheath passes. The fixing means has a threaded element to be screwed into a threaded orifice provided in a vehicle engine interface element to fix the temperature sensor to the engine interface element and a stop fixed to the insulating sheath. The stop surrounds the insulating sheath and provides sealing between the inside of the engine interface element and the outside, the threaded element being capable of rotating with respect to the stop. The stop comprises at least one lug that goes into a slot provided in the engine interface element to prevent the temperature sensor from rotating with respect to the engine interface element.

In order to provide a flow rate measurement device that can measure a flow rate of a sample fluid passing a tube body with high accuracy even though temperature irregularity of the sample fluid generates along a radial direction of the tube body, the flow rate measurement device comprise a temperature measurement device that measures a mean temperature of a sample fluid discharged from an internal combustion engine or temperature distribution of the sample fluid along a radial direction of the tube body, and a flow rate of the sample fluid is measured based on the mean temperature or the temperature distribution measured by the temperature measurement device.

A system for detecting spark plug failures in an engine is provided. The system may include one or more sensor devices coupled to the engine and configured to measure engine data, a controller in communication with the sensor devices, and an output device. The controller may be configured to determine at least a misfire count, a secondary transformer voltage, and an exhaust port temperature based on the engine data, identify a fault condition based on one or more of the misfire count, the secondary transformer voltage, and the exhaust port temperature, and perform a corrective action responsive to the fault condition. The output device may be configured to generate a notification corresponding to the fault condition.

A combustion speed, for example, is estimated or evaluated, with a required accuracy, more simply than the conventional art, while reducing man-hours to produce a heat generation rate waveform of an internal combustion engine. An increase rate of a heat generation rate relative to a change in a crank angle in a heat generation rate increasing period (e.g., a first-half combustion period a) in which the heat generation rate increases after ignition of an air-fuel mixture is defined as a heat generation rate gradient b/a that is one of characteristic values of the heat generation rate waveform. The heat generation rate gradient is estimated based on a fuel density (e.g., fuel density .sub.fuel@dQpeak at heat generation rate maximum time) at a predetermined time set in advance in the heat generation rate increasing period so as to produce the heat generation rate waveform using the estimated heat generation rate gradient.

A system to detect the presence of a catalyst includes an exhaust gas tube, a first temperature sensing device, a second temperature sensing device, a flow rate measurement device, and a processing device. The first temperature sensing device measures a first temperature of exhaust gas upstream of the exhaust gas tube. The second temperature sensing device measures a second temperature of the exhaust gas downstream of the exhaust gas tube. The processing device estimates an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding to a system with a catalyst present. The processing device may also determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.

This misfire detecting device for an internal combustion engine having a plurality of cylinders, for detecting a misfire of the internal combustion engine, is provided with: a pulsation component acquiring unit for performing a frequency analysis of operating parameter data indicating a change over time in an operating parameter correlated with an overall operating state of the plurality of cylinders, and for acquiring a pulsation component spectrum, which is a frequency spectrum of pulsations of the internal combustion engine; a difference parameter acquiring unit for acquiring a difference parameter correlated with a degree of difference between the operations of each of the plurality of cylinders; and all-cylinder misfire determining unit for determining that an all-cylinder misfire has occurred in the internal combustion engine if the pulsation component spectrum acquired by the pulsation component acquiring unit falls below a first threshold and the difference parameter acquired by the difference parameter acquiring unit 12 falls below a second threshold.

A method for operating an internal combustion engine having a plurality of cylinders includes: measuring, by exhaust gas sensors arranged at an exhaust gas of every cylinder for which cylinder-specific combustion control is carried out, for each respective cylinder, at least one actual combustion value; comparing each respective measured actual combustion value with a reference combustion value to determine at least one cylinder-specific control deviation for every cylinder for which cylinder-specific combustion control is carried out; determining at least one cylinder-specific control variable for every cylinder for which cylinder-specific combustion control is carried out based on the cylinder-specific control deviation or on every cylinder-specific control deviation; and operating each cylinder for which cylinder-specific combustion control is carried out based on the respective cylinder-specific control variable to bring the respective actual combustion value closer to the respective reference combustion value and minimize the respective control deviation.

A system for detecting spark plug failures in an engine is provided. The system may include one or more sensor devices coupled to the engine and configured to measure engine data, a controller in communication with the sensor devices, and an output device. The controller may be configured to determine at least a misfire count, a secondary transformer voltage, and an exhaust port temperature based on the engine data, identify a fault condition based on one or more of the misfire count, the secondary transformer voltage, and the exhaust port temperature, and perform a corrective action responsive to the fault condition. The output device may be configured to generate a notification corresponding to the fault condition.

A cylinder head of an internal combustion engine includes a first exhaust port section having an upstream inlet opened and closed by a first exhaust valve, a second exhaust port section having an upstream inlet opened and closed by a second exhaust valve, and a collective exhaust port section into which the first and second exhaust port sections merge at downstream ends thereof. In a fixing structure for an exhaust gas sensor, the sensor is fixed to the collective exhaust port section with its sensing tip in the port section. An exhaust gas guide part is formed, at a position upstream of the sensor, on an internal wall of the port section, opposite the internal wall to which the sensor is fixed, so as to bulge out to guide exhaust gas toward the sensor, whereby exhaust gas is effectively intermixed and directed to the sensor with resultant increased sensing accuracy.